Web dryer

ABSTRACT

A web dryer structure for thermal removal of moisture from a traveling web such as a web of paper coming from the press section of a papermaking machine including a row of upper dryer drums and a row of lower dryer drums with the drums positioned to carry the web in a serpentine path successively between the upper and lower drums and the web wrapping the upper and lower surfaces of the drums, respectively, with upper and lower looped felts wrapping the webs on the upper and lower surfaces of the drums and the felts guided by felt rolls positioned intermediate the spaces between the drums so that the web is controlled by felts in all locations as it travels between the drums.

0 United States Patent 1 1 [111 3,751,822

Crist Aug. 14, 1973 WEB DRYER 3,387,384 6/1968 Sutton 34/114 El E. 't Inventor met C v Primary Examiner-John J. Camby Assigneei Beloit 'l e Assistant Examiner-Henry C. Yuen W H [22] Filed, Dec Attorney-Hill, Sherman, Meroni, Gross & Simpson [21] App]. No.1 209,205 [57] SACT A web dryer structure for thermal removal of moisture 52 us. c1 34/116, 34/1 17, 34/123, from a traveling web such as a web of p p coming 34/120 from the press section of a papermaking machine in- 151 1111. C1. F26b 13/06 eluding a row of pp dryer drums and a row of lower [58] Field of Search 34/1 17, 166, 120, dryer drums with the drums Positioned to carry the web 34/ l l l, 116, 123, H4, 115, 122, 124 in a serpentine path successively between the upper and lower drums and the web wrapping the upper and [56] References Cited lower surfaces of the drums, respectively, with upper UNITED STATES PATENTS and lower looped felts wrapping the webs on the upper 3 378 936 4/1968 B 34 l 6 and lower surfaces of the drums and the felts guided by 6 12/1967 s i' g'' g 4 felt rolls positioned intermediate the spaces between 3283'415 11/1966 Schnyder 34/111 the drums so that the web is controlled by felts in all 10- 219501540 8/1960 Fleissner 34/115 as it "avels between the drums- 992,688 5/1911 Pope 34/117 17 C 4 Drawing Figures 3,316,657 5/1967 Haywood 34/116 PAIENJED we 1 Mars suszm er 3 FIG.

PATENTEDAUG 14 1973 3. 751.822

sums er FIG. 3

WEB DRYER BACKGROUND OF THE INVENTION The invention relates to improvements in dryers for drying fibrous webs and more particularly relates to an improved felt run arrangement for paper machine dryers.

Paper machine dryers usually include a series of rotating drying cylinders or drums arranged one after the other in two vertically spaced horizontally extending rows. The fibrous web is trained in a serpentine path to pass up and down between the drums. The web runs an on upper drying cylinder and then runs downwardly to partially wrap a lower drying cylinder. The web then again travels upwardly and partially wraps a next succeeding upper drying cylinder and so forth throughout the dryer section.

Separate felt runs are provided for the rows of upper and lower drying drums to hold the web to the drum surfaces as it travels over the upper and lower drums throughout the length of the dryer section. A series of felt idlers located between the upper and lower drying cylinders guides the felts to pass over the surfaces of the dryer cylinders. In conventional dryer sections the weight papers, there is a tendency for the wet sheet to relax as it passes around the initial drying cylinders. When entering the dryer section, the temperature of the web must first be raised to approximately the temperature of the drying cylinder surface and at high speeds this temperature elevation of the web may require as many as ten to fourteen drying cylinders. During this "warm-up phase very little drying is accomplished and no strength is added to the moist paper web. Flutter of the web commonly occurs during this initial warm-up phase." I

Attempts have been made for guiding the felt and web travel between the dryer drums to avoid the effects of flutter on the web and to eliminate the air currents which are believed to be the principal cause of web flutter. Examples of such efforts are shown in U.S. Pat. No. 3,355,816 issued to Thomas G. McKie and U.S. Pat. No. 3,419,203 issued to John W. Amend, Jr.

Other efforts to control these problems and to eliminate or reduce flutter have been numerous including positioning the dryer drums in closely spaced relation in an attempt to shorten the sheet draw between dryers. .This has proved disadvantageous because of the difficulties in sheet threading, felt changing and the difficulty of passing a large wad of paper between the closely spaced cylinders in the event of a sheet break. Efforts to ventilate the pockets between the felts or to break up the air layers carried on the felts or webs to prevent flutter have also not been wholly successful at high rates of speed because of the high volume of air to be handled.

A feature of the present invention is to eliminate the disadvantages of structures heretofore available by providing an arrangement wherein a web is always in contact with or in close proximity to a supporting felt during its travel through the dryer section to thereby control the web at all positions of travel between the upper and lower runs of dryer cylinders.

Another feature of the invention is to provide felt support rolls which are perforate and have means to force air through the felt for removing moisture.

A further feature of the invention is to provide felt support rolls for the lower felt positioned to run the lower felt upwardly so as to extend into the spaces in unique positions intermediate the upper drying cylinders and to provide felt support rolls for the upper felt so as to extend into the spaces in unique positions intermediate the lower drying cylinders.

A still further feature of the invention is to provide felt support rolls for the upper and lower felts of a dryer, which are located so as to minimize the effect of induced flows of air which have heretofore caused flutter of the web.

Another feature of the invention is to provide felt support rolls which are perforate and have means to force air through the felt for removing moisture therefrom and wherein the pockets formed beween the guided felts form passages for carrying away moisture laden air.

It is accordingly an object of the present invention to provide a machine with a thermal dryer section which is capable of handling traveling webs at a high rate of speed such as from 3,000 to 4,000 feet per minute or more with the web controlled to an extent that flutter thereof is substantially eliminated and stretching or tearing of the web does not occur.

A still further object of the invention is to provide an improved structural arrangement for a dryer section of a paper making machine using upper and lower rows of dryer drums wich permits the possibility of reconstruction of existing dryer section without relocating the dryer drums and with a minimum of reconstruction.

Other objects, advantages and features will become more apparent, including the equivalent structures and methods, from the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments in the specification, claims and drawings in which:

DESCRIPTION OF THE DRAWINGS FIG. I is a somewhat schematic showing of an end elevational view of a structure exemplifying prior art constructions;

FIG. la is'a fragmentary view showing the effects of flutter;

FIG. 2 is a somewhat schematic elevational view of a section of a dryer constructed and operating in accordance with the principles of the present invention;

FIG. 3 is a somewhat schematic showing of an end elevational view of another form of the invention.

DESCRIPTION OF PRIOR ART STRUCTURE FIG. 1 shows a portion of a dryer section of a paper making machine including a plurality of cylindrical drying drums 40, 41 and 42 with the drum 40 being in the upper tier of drying drums and the drums 41 and 42 being in the lower tier of drying drums. Between each of the drums of the upper and lower tiers, is located a felt guide idler roll 43. Felts F1 and F2 travel in serpentine paths over and between the upper and lower drums, respectively. A paper web W travels in a serpentine path through the upper and lower tiers of the drying drums alternating from the upper to the lower tier. The direction of the travel of the felts F1 and F2 and the web W is indicated by arrowed lines. I

With reference to the drying cylinder 41, it will be observed that this cylinder is partially wrapped by the web W and the felt F2, the web W being sandwiched between the outer periphery of the cylinder 41 and the felt F2. The felt which travels at the speed of travel of the web W carries on its surfaces a layer of air indicated generally by the numeral 44. This air layer 44 travels at substantially the same speed of the felt F2. If the layer of air is permitted to travel its natural course, the porosity of the felt F2 will permit the air to enter into the chamber C in the manner indicated by the arrows 45. Current commercial paper machinery tends toward using porous or foraminous felts usually referred to in the trade as open felts". It will thus be appreciated that the volume of air entering into the chamber C can be very substantial. These large quantities of air will therefore tend to cause an increase in the pressure within the chamber C to cause the web W to deviate from its intended path as indicated by the dotted line W]. This deviation from the web W will create an unstable condition which becomes particularly pronounced at the laterally spaced edges of the web W because the unstable condition is aggravated and increased by the out rushing air at the edges of the chamber C. This unstable condition at the edge of web W will cause the edge of the web to move rapidly back and forth and this phenomenon is usually referred to as web or sheet flutter. When the fluttering sheet approaches the next drying cylinder 40, it will be sandwiched between the outer periphery of the cylinder 40 and the upper felt F1. As the edge of the web passes into the rapidly closing gap between the felt F1 and the cylinder 40 this will cause the web edge to fold over on itself and this fold will drastically reduce the edge strength of the web and will result in tearing of the web either in the dryer suction or subsequent operations. One method which has been attempted to correct this condition is to eliminate the layer of air 44 from the surface of the felt F2 such as by directing a stream of fluid under pressure from a nozzle against the carrying surface to disrupt and remove the layer of air preventing its entry into the chamber C, and such an arrangement is shown in U.S. Patent 3,419,203, Amend, Jr. Other arrangements have been attempted to correct the effects of web flutter due to the induced flow of air as referred to above. The effects of sheet flutter are illustrated in the drawing, figure 1a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the dryer section of FIG. 2, are a plurality of upper dryer drums 50, 51 and 52. Below the upper tier of drums, is a lower tier including dryer drums 53, 54 and 55. The web, as shown by the broken line W, travels in a sinuous path back and forth between the upper and lower tiers wrapping itself over the upper surface of the upper drums and over the lower surface of the lower drums.

An upper felt Fl wraps itself over the upper surface of the webs on the upper drums. A lower felt F2 wraps itself over the web on the lower surface of the lower drums. The upper and lower felts are guided by upper and lower felt guide rolls positioned between the tiers of dryer drums. The felt guide rolls for the upper felt F, are shown at 56, 57 and 58. The felt guide rolls for the lower felt F2 are shown at 59 and 60. At the end of the section of the dryer, the upper felt is lead upwardly over a guide roll 61, and the lower felt is lead away from the section over a guide roll 62. As will be appreciated by those versed in the art, the felts are formed in loops and suitable guide and tensioning rolls are provided to guide the remainder of the felt loops.

While in conventional structures heretofore available, the felts have been guided between dryers drums over guide rolls positioned between the drums, in the present arrangement, the guide rolls are located offset from the spaces between the dryer drums so as to be located above the lower drums and below the upper drums. Thus, as illustrated in FIG. 2, the upper felt Fl when passing down over the upper dryer drum 50 is threaded around the idler guide roll 56 which is located beneath the dryer drum 50. After the felt passes around the guide roll 56, it is again threaded upwardly over the next upper dryer drum 51 and then is threaded down over the next guide roll 57 which is located beneath the dryer drum 51. The felt then passes upwardly over the next drum 52 and then downwardly around the next guideroll 58 which is located approximately beneath the center of the dryer drum 52.

Similarly, for the lower felt; after it is carried around the lower surface of the first lower dryer drum 53, it passes upwardly over the guide roll 59 which is located substantially above the dryer drum 53. The felt then passes downwardly over the second dryer drum 54 and then upwardly over the guide roll 60 which is located substantially directly above the second dryer drum 54.

The web passes first over the first upper drum 50 then downwardly over the first lower drum 53 and its amount of wrap over the drum 53 is increased by bringing the lower felt F2 up over the drum by the guide roll 59. The web W is of course supported during the time it is carried on the felt up to where it is taken off the felt at the guide roll 59 and passes up toward the upper dryer drum 51.

The supported run of the web is shown at Wa and after the web passes the felt guide roll 59, the run Wb is in close proximity or in controlled relationship with the upper web and its run Fla. In the arrangement of FIG. 2, the web run after it leaves the supported felt, passes in close proximity to the next felt, whereas in the arrangement of FIG. 3, the web passes in actual contact with the next felt. The circumstances of operation including the weight of the web, speed of operation and so forth will determine which of the arrangements of FIGS. 2 and 3 will be more satisfactory. In some circumstances where the the web is brought into direct contact with the felt, the pumped air carried along with the felt will tend to cause the web to separate from the felt. This separation is avoided in the arrangement of FIG. 2 and yet the web is maintained under control. In other words, a layer of air tends to follow along with the web over its run Wa. This layer of air will tend to pass through the felt in its run Fla.

Pockets formed below the upper dryer drums 51 and 52 as shown by the pockets 63 and 64. Similarly, pockets are formed above the lower dryer drums 54 and 55 as shown by the pockets 65 and 66. In a preferred form, the felt guide rolls are provided with a perforations and air pressure glands are located within the rolls to force air through the felts into the pockets. This tends to dry the felts and slightly pressurize the pockets also aiding in decreasing the tendency of the web flutter. The air directed into the pockets helps transfer the web from one felt to the other. The pressure glands within the guide rolls are rotationally adjustable for setting to an optimum position for operation. The pressurized air which is forced through the felts flows out of the open ends of the pockets.

The guide roll 59 has an air gland 59a which forces air through the lower felt F2 into the pocket 63. This air flows out of the ends of the pockets, inasmuch as the pocket is slightly pressurized this will help stablize the web in its run Wb. Rolls 57 and 58 are provided with air glands 57a and 58a, and roll 60 is provided with air gland 60a to respectively pressurize pockets 65, 66 and 64.

As will be noted from the drawing, the location of the felt guide rolls increases the area or length of wrap of the paper web W over the rolls. The web W is wrapped further around the off running side of lower roll 53 due to the location of the felt guide roll 59 above the roll 53. Similarly, the upper felt is wrapped further around the upper dryer drum 51 due to the location of the guide roll 57 beneath the dryer drum, thus increasing the wrap of the web on the off running side of this drum 51.

The distance between the web and the next felt, as the web leaves one felt to pass to the next tier of dryer drums is relatively small as indicated by the space between the web run Wb and the felt run Fla. This space is sufficiently wide to eliminate any problems which might be caused by entrapment of air carried up on the underside of the web in its run Wa, but to maintain the web close enough to the felt run Fla to prevent flutter of the web, in other words to maintain it under control. In the arrangement of FIG. 3, this control is obtained by bringing the web into actual contact with the next felt.

In the drawing of FIG. 3, the web W is received from a section of the machine in advance of the dryer section shown in the drawings. For example, the web may be received from the press section of the paper machine and will be shown at the location W in various positions through the dryer. The arrangement for leading the web into the dryer section is not important and suitable arrangements may be employed. As shown herein, the web is first received on a felt I ll passing over a vacuum roll 30 having a suction gland 30a for drawing the web into the felt ill.

The web is controlled throughout its path through the dryer section by upper and lower belts l0 and ill, respectively. These looped belts have additional overhead and lower supporting rolls not shown, and the belts may be of cotton, plastic or other material well known to the art of paper processing and are referred to as felts.

The dryer section includes a row of upper dryer drums l2, l3 and 14 which are cylindrical steam heated drums supported for rotation. Similar drums 15, 16 and 17 are arranged in a lower row staggered with respect to the positioning of the upper drums.

The upper felt is arranged to wrap the upper surfaces of the upper drums to hold the web thereto at high speeds. Similarly, the lower felt 1] is arranged to wrap the web on the lower surface of the lower drums for good heat transfer contact and to maintain the web tight to the drums at high speeds of travel. The upper felt is positioned to be led into the dryer section by guide roll lb, and the lower felt passes over the entry roll 30. The felts are guided in their paths of travel between the dryer drums by guide rolls. The guide rolls for the upper felts are shown at B9 and 20. These guide rolls draw the upper felt ill? down between the rolls and are laterally offset of the spaces between the rolls a distance so that they carry the web over to be picked up by the traveling lower felt l l, as will be more clear with a further detailed description of the travel and position of the felts.

The lower felt 1111 is guided in its travel between the lower dryer drums l5, l6 and T7 by lower guide rolls 2t, 22 and 23. These rolls guide the felts in their travel in the spaces between the drums and are positioned laterally offset (to the left as shown on the drawing) from the openings between the drums a sufficient distance so that they carry the web onto the traveling upper felt.

When the web enters the dryer section of the machine, it is carried by the lower felt H1 and is wrapped to the lower dryer drum t5 by the portion of the run Illa. As the web leaves the lower drum 15, it is carried on the lower felt run portion lllb. Before it leaves the lower felt, it is picked up by the upper felt in its run 10a and travels on run 10a up onto the upper dryer drum 112 to be wrapped thereover by the portion of the upper felt run Wb. Thus, the web in passing between the lower drum 115 and the upper drum 12 has been sup ported at all positions of its travel by first the lower felt and then the upper felt, and there has been no uncontrolled portion of travel which would permit uncontrollable flutter of the web. After passing over the upper drum 12, the web is carried by the upper felt in its run (where it is guided by the guide roll 19) and the web is then transferred to the lower felt in its run 11d. Transfer of the web is effected by the guide roll having an open pressure gland. For example, the web in being transferred from the run lttc of the upper felt to the run lltd of the lower felt, is transferred by the gland which blows heated air through the upper felt 10. The flow of air through the upper felt serves an additional purpose in that it dries the felt lltld. The flow of air slightly pressurizes the pocket 2% and helps aid the web in being firmly carried on the surface of the lower felt in its runs Tlld and llllf which expose the web to the pocket 2%. The air directed into the pocket is removed from the end of the pocket 2%. The slight pressure in the pocket also aids in preventing flutter of the felts so that the guide rolls such as 19 and 22 can be barely brought into touching contact with the felts that they meet. in other words, the roll 2d is positioned so that it presses only slightly against the lower felt run 11c, 11d. The run iltc is under pressure from the gland 21a supplying heated air through the felt ill into the pocket 25. Air is removed from this pocltet by suitable removal ducts, not shown, located at the ends of the pocket. The slight pressure in the pocket 25 helps hold the web against the upper felt in its run We and in its run We.

As the web travels downwardly after-being transferred from the upper felt at the location of the guide roll 19 to the lower felt, it passes along run ltd and then wraps the lower roll llb being held thereon by the lower felt in its run Me. The web then travels up along the run lllf of the lower felt and is transferred without an unsupported run to run we of the upper felt whereupon it passes over the top of the roll 13 being held thereagainst by the run llf of the upper felt. The web then travels, supported on the upper felt for the run 10g and is transferred to the lower felt for run llh and is wrapped over the lower roll by the felt for the portion of its run lli and then is carried up for the run 11] to be transferred to the upper felt for its run 101'. The pocket 29 is pressurized by the pressure gland a of the guide roll 20 and the moist air after traveling through the felt is removed from the ends of the pocket. The slight pressure in the pocket 29 helps hold the web against the felt runs 11h and llj. Guide roll 23 similarly has a heated air pressure gland 23a and air flowing through the felt is removed at the end of the pocket 27.

Thus, the web has been controlled throughout its path of travel between and over the dryer drums. As will be noted, the felt guides 19 and 20 for the upper rolls are moved to the left, and the felt guides 21, 22 and 23 for the lower felts are moved to the left and positioned slightly above the upper felt guide rolls l9 and 20. The guide rolls are moved laterally of the spaces between the rolls a sufficient distance so that the web will be controlled by being supported for its entire travel and will move directly from the lower felt to the upper felt and conversely from the upper felt to the lower felt. The pressurized guide rolls are positioned and arranged so that the flow of heated air through them aids in the transfer of the web from one felt to the other, helps dry the felts and additionally pressurizes the pockets for aiding in web control at high speeds.

As will be noted from contrasting structures of the prior art as shown in FIG. 1-, and the structures of the present invention as shown in FIGS. 2 and 3, the lower felts of FIGS. 2 and 3 are looped over guide rolls posi' tioned above the lower rolls, which guide rolls were conventionally used for upper felts in prior art structures. Similarly, the upper felts in accordance with the present invention, are looped over rolls positioned below the upper dryer drums, which the guide rolls were heretofore used for the lower felts. This unique and unobvious arrangement of FIGS. 2 and 3 has achieved substantial advantages in improved speed capabilities and consequent dryer capacities. It is of course necessary to provide longer felts then heretofore necessary, but the relatively small additional cost for longer felts is outweighed by the numerous other advantages.

The present invention utilizes the generic concepts of issued US. Pat. No. 3,250,019, issued to E. D. Beachler on May 10, 1966 and is an improvement thereof. Structures embodying the principles of the instant invention require only a single roll for guiding the felts between each of the adjacent lower dryer drums and each of the adjacent upper dryer drums. It is to be particularly noted that the upper and lower felts define a run for the web in passing between drums with one felt defining one portion of the run and other felt defining another portion of the run. The portions of the runs are at an angle to each other so that the web changes its direction of travel, although it is controlled at all locations in the run between the upper and lower tiers of drums. Inasmuch as the structures embodying the invention enable using only a single roll for the felts between drums less space is required and by threading the felts and minor repositioning of rolls of existing machines, the structures of the instant invention can be achieved without a complete rebuilding of existing machines. By the use of single guide rolls, the spacing between guide rolls and drums is larger so that wads of paper can readily pass in cases of web breakage. A flexability of design is afforded in that by shifting the position of a guide roll for the upper felt and a guide roll for the lower felt, the ratio between the portions of the runs can be changed. For example, the length of the portion of the run where the web is supported after leaving the drum, can be lengthen and the portion of the run of the next felt where the web is taken to the next drum can be shortened. Thus with the arrangement of FIG. 2 wherein the second portion of the web run is controlled, but not in actual supporting contact with the felt, this portion can be shortened to decrease any tendency flutter.

By the unique positioning of the guide rolls for the felts the dryer drum tiers can be brought closer together since the guide rolls essentially located in spaces between drums. That is the guide roll for the lower belt is located over a lower drum, or in the space between upper drums.

Another advantage which is achieved by having the portions of the web runs at an angle to each other, or in other words, in forming a knee in the path of travel is that it is believed that a change in direction of travel the web tends to throw off the layer of air traveling on the surface of the web to reduce the possibility of air layer buildup which lifts the web off the felt.

Further, when the web is under tension in the machine direction, by providing a knee or angle in the web run, the web tension tends to pull the web tightly against the supporting felt at the knee. Tenstion in the web in the machine direction can occur due to shrinkage of the web as it is drying. lt also can occur by machine operation wherein the dryer section is run at a slightly increased speed over the preceding press section of a paper making machine.

In some installations, a change in effect can be obtained by slightly shifting the angular position of the pressure gland within the guide roll, and for this purpose, angular adjustment means, not shown, is pro vided for the gland.

The term felt or belt as used herein means any of the various types of web supports known to those versed in the dryer art from a woven cotton belt to an open woven plastic screen or wire belt.

I claim as my invention:

1. A web processing device for conditioning a traveling web comprising in combination,

an upper drum adapted to carry a web,

a lower drum adapted to carry the web,

said web wrapping the upper and lower surfaces of the upper and lower drums respectively,

upper and lower belts wrapping the web on the drums,

upper and lower belt guide rolls for the upper and lower belts respectively,

said upper and lower guide rolls respectively positioned below and above the upper and lower drums to cause the belts to wrap their drums on the offrunning side and to guide the upper and lower belts toward each other into close running relationship between the drums so that the web is controlled for its entire travel between the upper and lower drums,

said belts defining a run for the web between drums with one belt defining one portion of the run and the other belt defining another portion of the run,

said portions being at an angle to each other.

2. A web processing device for conditioning a traveling web being constructed in accordance with claim 1 wherein:

said guide rolls are in positions so that the web is brought into actual supported contact when passing from one belt to another belt between drums.

3. A web processing device for conditioning a traveling web being constructed in accordance with claim 11 wherein:

said guide rolls are in positions so that as the web leaves one belt it has a slight space between it and the succeeding belt and travels at an angle approaching the belt to be in engagement therewith as the web engages the drum.

4. A web processing device for conditioning a traveling web being constructed in accordance with claim 1 wherein:

said guide rolls are perforate and have a pressure gland therein positioned to direct a flow of belt drying air through the belt at the location where the web moves out of supported engagement with the belt.

5. A web dryer structure for the thermal removal of moisture from a traveling web comprising in combination,

a plurality of rotatably mounted upper dryer drums adapted to be heated to carry a web and evaporate moisture therefrom,

a plurality of rotatably mounted lower dryer drums adapted to be heated to carry the web and evaporate moisture therefrom, said drums positioned to carry the web in a sinuous path passing successively between the upper and lower drums with the web wrapping their upper and lower surfaces respectively,

upper and lower looped belts formed of a pervious material accommodating the escape of water vapor from the web and wrapping the web on the upper and lower surfaces of the upper and lower drums respectively,

upper and lower belt guide rolls for the upper and lower belts respectively, first of said lower belt guide rolls positioned to carry the lower belt between a first and a second of said lower drums, and a first of said upper belt guide rolls positioned to carry the upper belt between a first and a second of said upper drums and located to carry the upper belt to bring the web into supporting contact with the lower belt so that the web is supported for its travel between the upper and lower rolls,

said belts defining a run for the web between drums with one belt defining one portion of the run and the other belt defining another portion of the run with said portions being at an angle to each other,

said guide rolls being laterally offset from the space between the drums in the same lateral direction.

6. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim wherein: said first lower guide roll is positioned over the first lower dryer drum.

7. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 5 and including a heated air discharge means for discharging air through the upper belt into the pocket between the belt and the second lower drum.

8. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 7 wherein the discharge means is located within said upper guide roll and the guide roll is perforate for the discharge of air through the belt while on the guide roll.

9. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 5 and including means for pressurizing the spaces between the lower surface of the upper drums and the upper surface of the lower drums and the belts for excluding extrinsic air currents.

10. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 5 and including a lead guide for the upper belt directing it in an upward path onto the first upper drum with the first lower guide roll positioned above the first lower drum to bring the web into contact with the belt in its uprunning path to the first upper drum, and including a lead roll for the lower belt receiving the web for carrying it to the dryer drums, and wherein each of said guide rolls is perforate and is provided with means for pressurizing the roll with heated air for driving heated drying air through the belts.

11. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 6 wherein lead guide means is provided so that the upper web travels in an upwardly path to the first upper drum and the first lower guide roll carries the lower belt to position the web in engagement with the upper belt as the web travels from the first lower to the first upper drum.

12. A web dryer structure for the thermal removal of moisture from a traveling web comprising in combination,

a plurality of rotatably mounted upper dryer drums adapted to be heated to carry a web and evaporate moisture therefrom, a plurality of rotatably mounted lower dryer drums adapted to be heated to carry the web and evaporate moisture therefrom, said drums positioned to carry the web in a sinuous path passing successively between the upper and lower drums with the web wrapping their upper and lower surfaces respectively,

upper and lower looped belts formed of a previous material accommodating the escape of water vapor from the web and wrapping the web on the upper and lower surfaces of the upper and lower drums respectively, and

single rolls carrying the belts between adjacent upper drums and between adjacent lower drums training said belts so that the web is supported by a belt at all positions in its travel between the upper and lower drums,

said guide rolls being laterally offset from the space between the drums in the same lateral direction.

13. A web dryer structure from the thermal removal of moisture from a traveling web constructed in accordance with claim 12 wherein the guide roll for the upper belt is at a lower elevation than the guide roll for the lower belt.

14. A web dryer structure for the thennal removal of moisture from a traveling web constructed in accordance with claim 12 wherein said guide rolls are positioned relative to the belts so that the belts and web wrap a greater are of the upper and lower dryer drums on the offrunning side then on the onrunning side.

15. A web dryer structure for the thermal removal of moisture from a traveling web comprising in combination,

a plurality of rotatably mounted upper dryer drums aapted to be heated to carry a web and evaporate moisture therefrom, a plurality of rotatably mounted lower dryer drums adapted to be heated to carry the web and evaporate moisture therefrom, said drums positioned to carry the web in a sinuous path passing successively between the upper and lower drums with the web wrapping their upper and lower surfaces, respectively,

upper and lower looped belts formed of a pervious material accommodating the escape of water vapor from the web and wrapping the web on the upper and lower surfaces of the upper and lower drums, respectively,

upper and lower belt guide rolls for the upper and lower belts, respectively,

said guide rolls positioned between the upper and lower rolls and located laterally of the spaces between the rolls a sufficient distance so that the web is in close running relationship with a belt for its entire travel between the upper and lower rolls and so that the web wraps unequal drum areas on the onrunning and offrunning sides of the drums.

16. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 15 wherein the guide rolls for the upper belts are located substantially directly under the upper drums and the guide rolls for these lower drums are located substantially directly over the lower drums.

17. A method of drying a web on a dryer section having a row of upper drying cylinders, a row of lower drying cylinders, upper felts wrapping the upper surfaces of the upper cylinders, and lower felts wrapping the lower surfaces of the lower cylinders with a web threaded sinuously between the upper and lower cylinders, the steps comprising:

guiding the web laterally of its normal path between upper and lower cylinders in each of the spans therebetween a distance to increase the wrap on the offrunning side and to keep the spans in close running relationship to the felts to maintain control thereover. 

1. A web processing device for conditioning a traveling web comprising in combination, an upper drum adapted to carry a web, a lower drum adapted to carry the web, said web wrapping the upper and lower surfaces of the upper and lower drums respectively, upper and lower belts wrapping the web on the drums, upper and lower belt guide rolls for the upper and lower belts respectively, said upper and lower guide rolls respectively positioned below and above the upper and lower drums to cause the belts to wrap their drums on the offrunning side and to guide the upper and lower belts toward each other into close running relationship between the drums so that the web is controlled for its entire travel between the upper and lower drums, said belts defining a run for the web between drums with one belt defining one portion of the run and the other belt defining another portion of the run, said portions being at an angle to each other.
 2. A web processing device for conditioning a traveling web being constructed in accordance with claim 1 wherein: said guide rolls are in positions so that the web is brought into actual supported contact when passing from one belt to another belt between drums.
 3. A web processing device for conditioning a traveling web being constructed in accordance with claim 1 wherein: said guide rolls are in positions so that as the web leaves one belt it has a slight space between it and the succeeding belt and travels at an angle approaching the belt to be in engagement therewith as the web engages the drum.
 4. A web processing device for conditioning a traveling web being constructed in accordance with claim 1 wherein: said guide rolls are perforate and have a pressure gland therein positioned to direct a flow of belt drying air through the belt at the location where the web moves out of supported engagement with the belt.
 5. A web dryer structure for the thermal removal of moisture from a traveling web comprising in combination, a plurality of rotatably mounted upper dryer drums adapted to be heated to carry a web and evaporate moisture therefrom, a plurality of rotatably mounted lower dryer drums adapted to be heated to carry the web and evaporate moisture therefrom, said drums positioned to carry the web in a sinuous path passing successively between the upper and lower drums with the web wrapping their upper and lower surfaces respectively, upper and lower looped belts formed of a pervious material accommodating the escape of water vapor from the web and wrapping the web on the upper and lower surfaces of the upper and lower drums respectively, upper and lower belt guide rolls for the upper and lower belts respectively, a first of said lower belt guide rolls positioned to carry the lower belt between a first and a second of said lower drums, and a first of said upper belt guide rolls positioned to carry the upper belt between a first and a second of said upper drums and located to carry the upper belt to bring the web into supporting contact with the lower belt so that the web is supported for its travel between the upper and lower rolls, said belts defining a run for the web between drums with one belt defining one portion of the run and the other belt defining another portion of the run with said portions being at an angle to each other, said guide rolls being laterally offset from the space between the drums in the same lateral direction.
 6. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 5 wherein: said first lower guide roll is positioned over the first lower dryer drum.
 7. A web dryer structure for the thermal removal of moisTure from a traveling web constructed in accordance with claim 5 and including a heated air discharge means for discharging air through the upper belt into the pocket between the belt and the second lower drum.
 8. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 7 wherein the discharge means is located within said upper guide roll and the guide roll is perforate for the discharge of air through the belt while on the guide roll.
 9. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 5 and including means for pressurizing the spaces between the lower surface of the upper drums and the upper surface of the lower drums and the belts for excluding extrinsic air currents.
 10. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 5 and including a lead guide for the upper belt directing it in an upward path onto the first upper drum with the first lower guide roll positioned above the first lower drum to bring the web into contact with the belt in its uprunning path to the first upper drum, and including a lead roll for the lower belt receiving the web for carrying it to the dryer drums, and wherein each of said guide rolls is perforate and is provided with means for pressurizing the roll with heated air for driving heated drying air through the belts.
 11. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 6 wherein lead guide means is provided so that the upper web travels in an upwardly path to the first upper drum and the first lower guide roll carries the lower belt to position the web in engagement with the upper belt as the web travels from the first lower to the first upper drum.
 12. A web dryer structure for the thermal removal of moisture from a traveling web comprising in combination, a plurality of rotatably mounted upper dryer drums adapted to be heated to carry a web and evaporate moisture therefrom, a plurality of rotatably mounted lower dryer drums adapted to be heated to carry the web and evaporate moisture therefrom, said drums positioned to carry the web in a sinuous path passing successively between the upper and lower drums with the web wrapping their upper and lower surfaces respectively, upper and lower looped belts formed of a previous material accommodating the escape of water vapor from the web and wrapping the web on the upper and lower surfaces of the upper and lower drums respectively, and single rolls carrying the belts between adjacent upper drums and between adjacent lower drums training said belts so that the web is supported by a belt at all positions in its travel between the upper and lower drums, said guide rolls being laterally offset from the space between the drums in the same lateral direction.
 13. A web dryer structure from the thermal removal of moisture from a traveling web constructed in accordance with claim 12 wherein the guide roll for the upper belt is at a lower elevation than the guide roll for the lower belt.
 14. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 12 wherein said guide rolls are positioned relative to the belts so that the belts and web wrap a greater arc of the upper and lower dryer drums on the offrunning side then on the onrunning side.
 15. A web dryer structure for the thermal removal of moisture from a traveling web comprising in combination, a plurality of rotatably mounted upper dryer drums aapted to be heated to carry a web and evaporate moisture therefrom, a plurality of rotatably mounted lower dryer drums adapted to be heated to carry the web and evaporate moisture therefrom, said drums positioned to carry the web in a sinuous path passing successively between the upper and lower drums with the web wrapping their upper and lower suRfaces, respectively, upper and lower looped belts formed of a pervious material accommodating the escape of water vapor from the web and wrapping the web on the upper and lower surfaces of the upper and lower drums, respectively, upper and lower belt guide rolls for the upper and lower belts, respectively, said guide rolls positioned between the upper and lower rolls and located laterally of the spaces between the rolls a sufficient distance so that the web is in close running relationship with a belt for its entire travel between the upper and lower rolls and so that the web wraps unequal drum areas on the onrunning and offrunning sides of the drums.
 16. A web dryer structure for the thermal removal of moisture from a traveling web constructed in accordance with claim 15 wherein the guide rolls for the upper belts are located substantially directly under the upper drums and the guide rolls for these lower drums are located substantially directly over the lower drums.
 17. A method of drying a web on a dryer section having a row of upper drying cylinders, a row of lower drying cylinders, upper felts wrapping the upper surfaces of the upper cylinders, and lower felts wrapping the lower surfaces of the lower cylinders with a web threaded sinuously between the upper and lower cylinders, the steps comprising: guiding the web laterally of its normal path between upper and lower cylinders in each of the spans therebetween a distance to increase the wrap on the offrunning side and to keep the spans in close running relationship to the felts to maintain control thereover. 